1. Field of the Invention
This invention relates to seating products such as seats and chairs, more specifically seating products having a back support that is adjustable to conform to the contour of the occupant.
2. Description of the Related Art
It is not uncommon for people to spend a substantial portion of their daily life sitting. As a result it is important that the seat be both safe and comfortable. One of the most important features of any seat is the manner in which it supports a user's back. If the seat provides inadequate support or supports the back in an improper position, the user is likely to become uncomfortable leading to an interruption in concentration, contribute to fatigue, poor posture, and even chronic back problems. On the other hand, a seat which provides the proper type of support may avoid, or even help to correct, such problems.
People are different in many respects, basic of which are size, shape, and strength. Because each person is unique, it is not uncommon that each person has a unique back support requirement. As a result, the ideal back support will vary from individual to individual.
Unfortunately, most seats have a back support designed for “the average individual.” In an effort to produce more comfortable and healthy seating, some seats, particularly those commonly used in the office environment, offer a variety of adjustment features, such as the height and angle of the back support. Other offer front and back adjustment of the seat. Not all seat manufacturers provide a full complement adjustment options so that one seat can fit any user. Many adjustment features do not satisfy the demand requirements of the public to justify their implementation. Other adjustment options are simply too expensive to offer. As a result, such seats cannot provide everyone the proper fit and support.
Many attempts have been made to improve the comfort of seating products. For example, the seat described in U.S. Pat. No. 3,990,742 to Glass has a number of individual cam-like members extending laterally across the seat back. These members can be individually rotated to modify the shape of the back support. Although this type of system offers increased adjustability, it sacrifices convenience. Given the number of cam members that must be adjusted for each user, it is impractical for a variety of users to use such a seat. Another seat having a number of individually adjustable back support members is disclosed in U.S. Pat. No. 5,018,786. Again, given the large number of individual adjustments necessary to configure the seat to each user, this type of seat suffers the same disadvantages as that described immediately above.
Some seats offer automatic adjustment systems. For example, U.S. Pat. No. 4,944,554 to Gross employs a number of motors to automatically adjust the configuration of a seat to a predetermined spinal profile. However, the complicated electrical and mechanical interfaces required for this type of seat limit its reliability, availability, and practicality in many environments.
U.S. Pat. No. 5,328,245 discloses a seat having a seat and an upwardly extending support bar. A number of segments are received along the support bar to define a support surface for supporting the back of the user. The segments are slidable back and forth in a direction perpendicular to the user to allow the support surface to conform to the back of the seated person. A locking mechanism allows the person to lock the segments in the desired position. The disadvantage offered by this invention is that the contour is not truly conforming. Rather the contour is obtained by a series of step-like adjustments resulting in sharp transitions along the contour.
Each of the chairs and seats mentioned above has one or more disadvantages. Most of the seats described above provide a complex contouring mechanism for adapting to the user's back. That is to say that the contouring mechanisms are so time consuming or difficult to configure to the user's back that most user's will find them impractical. Others of the seat designs mentioned above offer complex systems for conforming to the back of the occupant resulting in substantially higher costs which translate directly to higher prices for consumers. As a consequence seating products available on the market today appeal to a limited audience and fail to meet the mass market attributes of the day.